Multiple Tables!? Why bother?

Guillaume's employer, BastilleCo, believed in an egalitarian workplace. Managers and executives sat at the same desks as other employees, and they often took lunch together. This made BastilleCo an excellent workplace, even in a progressive nation like France.

However, BastilleCo's defect was to treat its data like it treats its employees. There existed the typical messiness of bad legacy code -- single-letter variables, globally-scoped functions, and so on. But not only was there no executive/employee segregation, but there was no data segregation either. In fact, there was a single table, where everything in BastilleCo's flagship application was stored:

It made SELECT statements easier to write, since you didn't need to remember a dozen table names, but there was little to tell one column apart from another. A developer could think they're selecting the FirstName column for Users, but it could be for Clients if they read the column name too quickly.